There has long been a need for a simple, economical device for raising and inverting a container such as a steel drum, for dumping the contents, and for reversing the container to the original position.
Corbin U.S. Pat. No. 4,385,860, describes a drum dumping attachment for a fork lift truck in which the drum is caused to pivot by engagement of a forwardly projecting finger with the rim of a receptacle for the drum contents. Locking pins, which are manually removable, prevent unwanted pivoting. The receptacle must have a rearwardly projecting tripping projection on its upper edge to engage the forwardly projecting finger on the device.
Glewwe, U.S. Pat. No. 3,893,579, and Kvalheim, U.S. Pat. No. 4,405,278, describe devices which are not simple. The Glewwe device is attached to a fork lift truck. Kvalheim describes a self-emptying dump box which engages a bracket attached to an upper edge of the receptacle for the contents of the dump box.